本文来源：huang_xw 的《Oracle数据库的状态查询》

1 状态查询

启动状态	SQL语句	结果
nomount	select status from v$instance;	STARTED
	select open_mode from v$database;	ERROR at line 1: ORA-01507: database not mounted
mount	select status from v$instance;	MOUNTED
	select open_mode from v$database;	MOUNTED
open	select status from v$instance;	OPEN
	select open_mode from v$database;	READ WRITE 或者 READ ONLY

2 实验过程

  1 SQL> startup nomount;

  2 ORACLE instance started.

  3

  4 Total System Global Area  125829120 bytes

  5 Fixed Size                  1247684 bytes

  6 Variable Size              92276284 bytes

  7 Database Buffers           25165824 bytes

  8 Redo Buffers                7139328 bytes

  9

 10 SQL> select status from v$instance;

 11

 12 STATUS

 13 ------------

 14 STARTED

 15

 16 SQL> select open_mode from v$database;

 17 select open_mode from v$database

 18 *

 19 ERROR at line 1:

 20 ORA-01507: database not mounted

 21

 22 SQL> alter database mount;

 23

 24 Database altered.

 25

 26 SQL> select status from v$instance;

 27

 28 STATUS

 29 ------------

 30 MOUNTED

 31

 32 SQL> select open_mode from v$database;

 33

 34 OPEN_MODE

 35 ----------

 36 MOUNTED

 37

 38 SQL> alter database open;

 39

 40 Database altered.

 41

 42 SQL> select status from v$instance;

 43

 44 STATUS

 45 ------------

 46 OPEN

 47

 48 SQL> select open_mode from v$database;

 49

 50 OPEN_MODE

 51 ----------

 52 READ WRITE